I removed the jumpers and the cap, and the +5 didn't change. It's still too low to make me happy, after doing all the pinwiki suggested fixes. I'll figure that out, I'm sure, but I can't figure out why someone would splice a cap between the regulator and ground?

Any thoughts?

driver.jpg

#2 9 years ago

ALX

donjagra

Pinside member

14y 72,100 3,402 10 34

Caps regulate?

#3 9 years ago

KLB

kbliznick

Firebird Pinball

Phoenix, AZ

11y 63,900 2,438 5 4

On all of the driver boards the small cap on the front side of the board just to the right of the heatsink is in the wrong place. You can see the two vias for it in the picture just to the left of the burned area. The factory placement puts it across the input and the ground, where the schematics depict it across the output and the ground.
The input already has the 15,000 uf cap on it so adding the 1 uf cap on the same input side does nothing.

This was probably someones attempt to fix that.

Weird revision of the driver board you have. Can't recall ever seeing the ground trace going to the upper screw.

#4 9 years ago

JWJ

johnwartjr

That Pinball Place

Columbus, IN

12y 77,400 6,479 14

That makes sense, I have not been able to figure out what game this driver came in originally , it has the older serial # style, and the first half of the serial # doesn't resemble any game #.

#5 9 years ago

MAR

MarAlb

Pinside member

Zeist

9y 53,650 814 19

Smaller (ceramic) capacitors do have better characteristics to deal with Higher Frequency noise. It also deals with coupling between the traces to the LM323 if there is any.

#6 9 years ago

KLB

kbliznick

Firebird Pinball

Phoenix, AZ

11y 63,900 2,438 5 4

OP
Quoted from johnwartjr:
That makes sense, I have not been able to figure out what game this driver came in originally , it has the older serial # style, and the first half of the serial # doesn't resemble any game #.

Dr Dude maybe?

#7 9 years ago

TOX

ChrisHibler

Chris' Pinball Repair

Chesterfield, MO

12y 120K 9,996 46

More info about the hack.
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#WPC_Power.2FDriver_Board_Layout_Error
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball RepairInfo

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